Study On The Preparation And Properties Of Bacterial Cellulose-Based Dressings

Bacterial cellulose(BC),a kind of nano-molecular material,with high water absorption and high water retention performance and good water vapor transmission rate.The compound of BC dressing is prepared by compounding bacterial cellulose with drugs for treating wounds.Heparin,a high molecular weight glycosaminoglycan,which has anti-inflammatory effect,can induce growth factor to cell proliferation,tissue repair and regeneration,can promote wound microcirculation,reduce wound pain,and promote wound healing.Collagen,a polysaccharide protein,which has good biocompatibility,biodegradability and low immunogenicity,has hemostatic function and promotes cell growth.BC/Hep dressings was prepared by adding heparin to bacterial cellulose medium,and modified with crosslinking agent and characterized.Then,BC/Hep/COL dressings was prepared by adding heparin and collagen to bacterial cellulose medium,and modified and characterized.Through the comparison of performance,we can get the dressings with better performance.The detail researches are as follows:(1)Preparation and characterization of BC/Hep dressings:BC/Hep dressings were prepared in situ by adding heparin to the culture medium of bacterial cellulose and cross-linked with different molar ratios of cross-linking agent,and its structure,drug release and dressing properties were studied.The results shows that:with the increase of the concentration of crosslinking agent,the heparin content increased from 66569.06 ?g/g to 82817.82 6?g/g,but less than the load of uncrosslinked BC/Hep.The release of heparin from BC/Hep dressings is consistent with the Peppas model.The release mechanism is Fick diffusion.When the molar ratio of the cross-linking agent is EDC:NHS:Hep-COOH=0.4:0.24:1,the mechanical properties are enhanced,the sustained release of heparin is controlled,the water absorption performance is the best,and the water vapor transmission rate is 814.10 ± 44.87g/m2/d,which is the optimal crosslinking agent molar ratio.(2)Preparation and characterization of BC/Hep/COL dressings:BC/Hep/COL dressings were prepared in situ by adding heparin to the culture medium of bacterial cellulose and cross-linked with different molar ratios of cross-linking agents,and its structure,drug release and dressing properties were studied.The results shows that:with the increase of the concentration of crosslinking agent,the heparin content increased from 49824.98 ?g/g to 64740.53 ?g/g but less than the load of uncrosslinked BC/Hep/COL.The release of heparin from BC/Hep/OL dressings is consistent with the Peppas model.The release mechanism is Fick diffusion.After adding collagen,the loading of heparin in the dressing and the cumulative release rate within 24 hours were less than that of BC/Hep.The mechanical properties,water absorption and water retention properties of the dressings increase,and the moisture permeability decreases after adding collagen.For BC/Hep/COL dressings,the optimal crosslinking agent molar ratio was also EDC:NHS:Hep-COOH=0.4:0.24:1.